Weir grates provide a design alternative to floor-mounted drainage grates (also known as drainage wastes) that comprise multiple holes, often forming a pattern. Weir and drainage grates are predominantly die-cast because this technique allows for low-cost and mass production of grates of acceptable quality, using brass, zinc and other non-ferrous metals. The technique is able to produce complicated grate shapes, but requires an electro-plating step to obtain a grate with a surface appearance that is acceptable to a consumer (e.g. a chrome-like polished surface finish).
To enable grates to be directly formed from higher melting point ferrous metals such as stainless steel, investment casting has been employed. However, compared to die-casting, investment casting results in increased production time, lower volume output, more costly casting raw materials, thicker walled products and, often, the need for a subsequent wall straightening step.
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